U.S. Pat. No. 4,817,664 granted to the same applicant of this application discloses a switch valve provided in a throttle nozzle between an inlet passage and a pressure sensing chamber containing a diaphragm controlling a lever arrangement. Everytime an exhausted gas line having such a conventional gas pressure regulator is used, a main valve of a gas bottle is opened to cause a suddenly increased gas flow volume through the gas regulator, the switch valve 260 will close the throttle hole 203 which should be re-opened by operating the restoring mechanism 270 for re-use of gas, causing operation inconvenience for the user.
Chuang Jung-chao disclosed a safety controlled valve in his U.S. Pat. No. 4,579,142 which may automatically shut off the gas inlet side 11 by a ball valve 7 once opening a main valve of a gas source for using the gas. After closing the valve 7, it should be restored by operating a cover button 1 to open the valve 7 for reusing the gas, still causing inconvenience for a gas user.
The present inventor has found the drawbacks of my original invention and the prior art such as Chuang's device, and invented the present gas pressure regulator for saving the resetting operation of the throttle valve.